The present invention relates to the field of optical-fiber communication links and more particularly to a method of reducing the intermodulation distortion found to occur in link systems. Analog optical-fiber communication systems are being actively developed as substitutes for conventional electromagnetic transmission lines. One system that has proven especially attractive is to employ a constant power optical source, such as a laser diode, in conjunction with an external modulator. Unfortunately, in this system, the dynamic range is limited by intermodulation distortion and harmonic distortion resulting from modulator nonlinearities. A need exists, therefore, for a method and apparatus that significantly reduces such modulator nonlinearities.